It is necessary to test the completion of nonblocking operations
before any of the resources specified in the nonblocking routine can
be reused. ADIO provides three kinds of routines for this purpose: a
quick test for completion that requires no further action (ADIO_xxxxDone), a test-and-complete (ADIO_xxxxIcomplete), and
a wait-for-completion (ADIO_xxxxComplete).
Separate routines exist for read and write operations.

int ADIO_ReadDone(ADIO_Request *request)
Similarly ADIO_WriteDone.

These routines check the request handle to determine whether the
operation is complete and requires no further action.
They return true if complete, and false otherwise.

If an operation is not complete, the above routines can be used.
Note that these routines do not block waiting for the operation
to complete. Instead, they perform some additional processing
necessary to complete the operation. If the operation is completed,
they return true and set the status variable; otherwise, they
return false. If an error is detected, they return true and set the
error_code appropriately.